请阅读这个 in red.

(2) A tenant is not guilty of an unlawful detainer pursuant to subdivision (e) of Section 798.56 of the Civil Code or paragraphs (2) and (3) of Section 1161 if, within 15 days of service of the notice, excluding Saturdays and Sundays and other judicial holidays, the tenant either makes the demanded payment or vacates.

(b) A notice shall be deemed void and insufficient to support a judgment for unlawful detainer under paragraphs (2) and (3) of Section 1161, or to terminate a tenancy under subdivision (e) of Section 798.56 of the Civil Code, if it is served during the 12 months immediately after the covered time period ends and it fails to comply strictly with subdivision (a).

也就是说，2021／4／1以后十二个月内发的因为欠租而驱逐的通知都无效。

当然，如果是因为其他原因而驱逐（吸烟，未经同意养狗，私自转租），我认为今天就可以开始。